GPT-5.1 Codex

OpenAI's GPT-5.1 variant optimized for agentic coding in Codex workflows.

Agentic CodingCodex OptimizedSnapshot Model

Context Window

400,000

GPT-5.1 Codex

Max Output

128,000

1M tokens

Input

$1.25

Output

$10

Model Codegpt-5.1-codex

Playground

Model Code

gpt-5.1-codex

Enter your prompt here...

Output

No output yet

Pricing

Plan	Context Window	Max Output	Input	Output	Cache Write	Cache Read
GPT-5.1 Codex	400,000	128,000	$1.25	$10	-	$0.125

Official OpenAI pricing for GPT-5.1-Codex.

Cached input pricing applies to reused prompt tokens.

Cache read or cached input pricing applies to reused prompt tokens.

README

GPT-5.1 Codex is a coding-specialized GPT-5.1 model tuned for long-horizon software tasks, agentic implementation, and robust coding reliability in Codex-style environments.

OpenAI describes GPT-5.1-Codex as a GPT-5.1 variant optimized for coding and available as regularly updated snapshots.
It is designed for complex implementation tasks where code quality, tool use, and longer task horizons matter.
Compared with general-purpose models, GPT-5.1 Codex is positioned for software workflows and agentic development loops.

API

Use the API docs for request format, parameters, and integration details.

OpenAI's GPT-5.1 variant optimized for agentic coding in Codex workflows.

Model Code

gpt-5.1-codex

View API Docs

API

Endpoint

POST /v1/responses

Authentication

Authorization: Bearer YOUR_REACH_API_KEY
Content-Type: application/json

Example

curl -X POST "https://direct.reachapi.ai/v1/responses" \
  -H "Authorization: Bearer YOUR_REACH_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "YOUR_MODEL_ID",
    "input": "Introduce ReachAPI in one sentence.",
    "temperature": 0.2
  }'

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